Microstructure and Strength of gamma-TiAl alloy/Inconel 718 brazed joints

• Type: Article in International Conference Proceedings Book
• Date: 2013

Authors

Sequeiros, EW (Author) Other; Guedes, A (Author) Other; Pinto, AMP (Author) Other; Vieira, MF (Author) FEUP; Viana, F (Author) FEUP

Conference proceedings International

Title: ADVANCED MATERIALS FORUM VI, PTS 1 AND 2

Pages: 835-840

6th International Materials Symposium (MATERIALS 2011)/15th Meeting of SPM

Guimaraes, PORTUGAL, APR 18-20, 2011

Indexing

ISI Web of Knowledge - 7 Citations

Scopus - 12 Citations

Scientific classification

FOS: Engineering and technology > Materials engineering

Other information

Authenticus ID: P-005-3Q2

DOI: 10.4028/www.scientific.net/msf.730-732.835

Abstract (EN): Intermetallics and superalloys brazing development is a current topic owing the extending use of these alloys in industrial applications. In this work a gamma-TiAl alloy was joined to Inconel 718 by active metal brazing, using Incusil-ABA as filler. Joining was performed at 730 degrees C, 830 degrees C and 930 degrees C, with a 10 min dwelling time. The interfaces were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and Electron Backscatter Diffraction (EBSD). For all processing conditions, the reaction between the base materials and the braze alloy produced multilayered interfaces. For all processing temperatures tested (Ag), (Cu), AlNi2Ti and AlCu2Ti were identified at the interface. Raising the brazing temperature increased the thickness of the interface and coarsened its microstructure. The increase of the extension of the interface was essentially due to the growth of the reaction layers formed near each base material, which were found to be mainly composed of intermetallic compounds. The mechanical behavior of the joints, at room temperature, was assessed by microhardness and shear tests. For all processing conditions the hardness decreases from periphery towards the Ag-rich centre of the joints. Brazing at 730 degrees C for 10 min produced the joints with the highest average shear strength (228+/-83 MPa). SEM and EDS analysis of the fracture surfaces revealed that fracture of joints always occurred across the interface, preferentially through the hard layer, essentially composed of AlNi2Ti, resulting from the reaction between Inconel 718 and the braze alloy.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6